head {utils} | R Documentation |
Returns the first or last parts of a vector, matrix, table, data frame
or function. Since head()
and tail()
are generic
functions, they may also have been extended to other classes.
head(x, ...)
## Default S3 method:
head(x, n = 6L, ...)
## S3 method for class 'data.frame'
head(x, n = 6L, ...)
## S3 method for class 'matrix'
head(x, n = 6L, ...)
## S3 method for class 'ftable'
head(x, n = 6L, ...)
## S3 method for class 'table'
head(x, n = 6L, ...)
## S3 method for class 'function'
head(x, n = 6L, ...)
tail(x, ...)
## Default S3 method:
tail(x, n = 6L, ...)
## S3 method for class 'data.frame'
tail(x, n = 6L, ...)
## S3 method for class 'matrix'
tail(x, n = 6L, addrownums = TRUE, ...)
## S3 method for class 'ftable'
tail(x, n = 6L, addrownums = FALSE, ...)
## S3 method for class 'table'
tail(x, n = 6L, addrownums = TRUE, ...)
## S3 method for class 'function'
tail(x, n = 6L, ...)
x |
an object |
n |
a single integer. If positive, size for the resulting
object: number of elements for a vector (including lists), rows for
a matrix or data frame or lines for a function. If negative, all but
the |
addrownums |
if there are no row names, create them from the row numbers. |
... |
arguments to be passed to or from other methods. |
For matrices, 2-dim tables and data frames, head()
(tail()
) returns
the first (last) n
rows when n > 0
or all but the
last (first) n
rows when n < 0
. head.matrix()
and
tail.matrix()
are exported. For functions, the
lines of the deparsed function are returned as character strings.
If a matrix has no row names, then tail()
will add row names of
the form "[n,]"
to the result, so that it looks similar to the
last lines of x
when printed. Setting addrownums =
FALSE
suppresses this behaviour.
An object (usually) like x
but generally smaller. For
ftable
objects x
, a transformed format(x)
.
Patrick Burns, improved and corrected by R-Core. Negative argument added by Vincent Goulet.
head(letters)
head(letters, n = -6L)
head(freeny.x, n = 10L)
head(freeny.y)
tail(letters)
tail(letters, n = -6L)
tail(freeny.x)
tail(freeny.y)
tail(library)
head(stats::ftable(Titanic))